Reword confusable idents lint

Fix #76140.

compiler/rustc_lint/src/lints.rs

@@ -1056,8 +1056,10 @@ pub struct IdentifierUncommonCodepoints;
 pub struct ConfusableIdentifierPair {
     pub existing_sym: Symbol,
     pub sym: Symbol,
-    #[label]
+    #[label(lint_other_use)]
     pub label: Span,
+    #[label(lint_current_use)]
+    pub main_label: Span,
 }
 
 #[derive(LintDiagnostic)]

compiler/rustc_lint/src/non_ascii_idents.rs

@@ -222,6 +222,7 @@ impl EarlyLintPass for NonAsciiIdents {
                                     existing_sym: *existing_symbol,
                                     sym: symbol,
                                     label: *existing_span,
+                                    main_label: sp,
                                 },
                             );
                         }